1. Field of the Invention
The present invention relates to a solid state image sensor. More particularly, the present invention relates to a solid state image sensor to be used for a digital still camera or a digital video camera.
2. Description of the Related Art
Japanese Patent No. 3,592,147 discloses a solid-state imaging device having an image sensor with some of its pixels provided with a ranging function for detecting distances by phase detection as a distance sensing technique for ranging to be used for digital still cameras and digital video cameras.
Unlike conventional contrast measurement systems, the disclosed solid-state imaging device does not need to drive a lens for measuring distances and hence can operate for high precision ranging at high speed. Additionally the disclosed solid-state imaging device can operate for real time ranging when picking up a moving image.
With regard to the structure of the ranging pixels, each of the ranging pixels has between a micro-lens and a photoelectric conversion section an aperture that is off centered with respect to the optical center of the micro-lens.
This arrangement enables selective introduction of light that passes through a predetermined region on the pupil of the camera lens to the photoelectric conversion section to carry out ranging.